In recent years, light emission efficiency of light-emitting diodes (LEDs) has improved to such an extent that LEDs are attracting attention as a light source for general illumination use. In order to drive LEDs, a DC power supply is required.
A conventional DC power supply circuit is proposed that converts AC supplied from a residential AC power supply into DC, and thus outputs DC (refer to Patent Literature 1). Patent Literature 1 discloses a DC power supply circuit that includes a rectifier circuit, a smoothing capacitor that is connected across output terminals of the rectifier circuit, and a voltage conversion circuit that is connected across terminals of the capacitor, converts voltage across the terminals of the capacitor, and outputs a converted voltage.